1. Field of the Invention
Exemplary aspects of the present invention generally relate to an image forming apparatus such as a printer, copier, plotter, facsimile machine, or multifunction device having two or more of these capabilities.
2. Description of the Related Art
One type of image forming apparatus, such as a printer, copier, plotter, facsimile machine, or multifunction device having two or more of these capabilities, is an inkjet recording device employing a liquid ejection recording method. The inkjet recording device includes a recording head that ejects droplets of a recording liquid such as ink from nozzles in the recording head onto a sheet of recording media to form an image on the sheet. Examples of the inkjet recording device include a serial-type image forming apparatus, in which the recording head ejects ink droplets while moving in a main scanning direction to form an image on the sheet, and a line-type image forming apparatus equipped with a line-type recording head that ejects ink droplets while remaining stationary to form an image on the sheet.
The image forming apparatus generally includes a sheet feed tray attached to the image forming apparatus or a sheet feed cassette detachably attachable to the image forming apparatus, from which the sheet is fed to the image forming apparatus. It is to be noted that, in this specification, the sheet feed tray is either mounted or detachably attached to the image forming apparatus and need not be detached from the image forming apparatus upon supply of sheets to the sheet feed tray, whereas the sheet feed cassette is detachably attached to the image forming apparatus and needs to be withdrawn or detached from the image forming apparatus to resupply the sheets.
The sheet feed cassette is generally disposed near the bottom portion of the image forming apparatus. In a compact image forming apparatus, a mechanism for sheet feeding and sheet separation is often provided on the opposite side from a grip of the sheet feed cassette used for withdrawing the sheet feed cassette from the image forming apparatus upon, for example, supply of the sheets to the sheet feed cassette.
In addition, a discharge tray to which the sheet having the image formed thereon is discharged is generally disposed above and adjacent to the sheet feed cassette in order to make the image forming apparatus more compact. The discharge tray is often hinged to allow the sheet feed cassette to be opened and closed, thereby facilitating removal of jammed or misplaced sheets. However, because the above-described configuration allows supply of the sheets without detaching the sheet feed cassette from the image forming apparatus, the sheets may be improperly supplied to the sheet feed cassette.
For the purpose of properly supplying the sheets to the sheet feed cassette by opening a cover, that is, the discharge tray, from the sheet feed cassette, there is known a configuration that prevents the discharge tray from swinging open from the sheet feed cassette and thus preventing supply of the sheets to the sheet feed cassette unless the sheet feed cassette is withdrawn to a certain position from the image forming apparatus. In addition, a stopper mechanism that prevents insertion of the sheet feed cassette into the image forming apparatus when the discharge tray swings open from the sheet feed cassette may be used.
However, the stopper mechanism requires a large installation space especially in a width direction of the image forming apparatus perpendicular to a direction of withdrawal of the sheet feed cassette from the image forming apparatus, thereby preventing reduction in the size of the image forming apparatus.